Refueling of a hydrogen vehicle is basically concerned with how the refueling can be performed safely and without over-fueling the vehicle tank.
One method is described in SAE J2601 directing how a refueling can be safely executed without the risk of over-fueling the vehicle tank.
Various prior art methods may be attempted adapted to comply with the above-mentioned standard. One such method is described in EP1336795. Here an electric controller has knowledge of the rated density of a full vehicle tank, knowledge which is obtained from the manufacture of the tank. The electric controller is then periodically during the refueling, based on temperature and pressure signals from inside the tank, calculating the density in the receiving tank. When the calculated density is less than the tank rated density a flow is allowed to the tank and when the calculated density is higher than the tank rated density the flow is discontinued. When the density in the tank is equal to or higher than the rated density, the electric controller is waiting for the instrument to settle and if the density is still above rated density the refueling is complete. If not, the refueling is again resumed, thereby establishing a refueling of a number of refueling cycles. In this way over time, the effective stop criterion is a calculated density equaling the tank rated density.
A challenge in relation to this and other known refueling methods are that they may be relatively inefficient considering both the filling procedure and the resulting degree of refueling. It is in particular noted that consumers may find the known methods to deviate too much from refueling methods already known to the users when applying conventional fuel, such as gasoline.